The spread of a lethal bat disease to Georgia and South Carolina once again heightens concerns that humans may be implicated in the transmission of the fungal spores that causewhite-nose syndrome.

State and federal officials announcing the discovery of the disease in southeastern bat populations warned that there’s growing evidence that humans are a factor in the spread. White-nose syndrome has now spread to 22 states and 5 Canadian provinces over the past seven years.

The most recent discovery of the disease was made at two caves in Dade County, Ga. — one in the Chickamauga and Chattanooga National Military Park, operated by the National Park Service, and the other at Cloudland Canyon State Park. Last year the bat disease was documented on the Tennessee side of the same national military park.

“White-nose syndrome’s attack on North American bats is continuing unabated,” said Mollie Matteson, a bat specialist at the Center for Biological Diversity. “Unfortunately, despite the disease’s relentless push across the country, the response of state and federal wildlife agencies has been astonishingly passive.”

The bat disease, first documented in a cave in upstate New York in 2006, has spread as far west as Missouri. In the past month, it was reported for the first time in Illinois and Prince Edward Island, Canada. Biologists estimate it has killed nearly 7 million bats; so far it has affected seven species, including two that are federally endangered, the Indiana bat and the gray bat. Scientists fear the continued spread of the disease, which strikes bats during hibernation, will lead to the endangerment and possible extinction of many of North America’s two dozen hibernating bat species.

There is no cure for white-nose syndrome, which is caused by an introduced fungus, almost certainly from Europe, where the fungus is found but does not make bats sick. According to Matteson, scientists have collected compelling evidence that the fungus was brought to North America by cave visitors.

Given that humans may be carriers of the spore, Matteson said resource managers need to do much more to protect as-yet unscathed bat populations in he West, including stricter cave management rules and even closures of caves, a strategy deemed ineffective by cave-access groups.

Caves on U.S. Forest Service and National Park Service lands in Georgia have been closed to nonessential access since 2009.

“It’s chillingly clear that the next frontier for this devastating disease is the western United States and the many, many bat species that live there,” Matteson said. “But even now, our government officials keep allowing cave visitors to come and go in most western caves on federal land, as though nothing has changed in the past seven years. That needs to stop, or bat populations across the West may crash.”

The epidemic’s impacts are not limited to bats. Scientists estimate that the value of bug-eating bats to U.S. farmers ranges from $3 billion to $53 billion per year. Bats eat enormous quantities of moths, beetles, mosquitoes and other insects, and their absence could make farmers and others decide to use greater quantities of expensive, and potentially harmful, pesticides.